Optical fibers are widely used in a variety of applications, including the telecommunications industry in which optical fibers are employed in a number of telephone and data transmission applications. Due, at least in part to the extremely wide bandwidth and the low noise operation provided by optical fibers, the use of optical fibers and the variety of applications in which optical fibers are used are continuing to increase. For example, optical fibers no longer serve as merely a medium for long distance signal transmission, but are being increasingly routed directly to the home, or in some instances, directly to a desk or other work location.
With the ever increasing and varied use of optical fibers, it is apparent that efficient methods of coupling optical fibers, such as to other optical fibers, to a patch panel in a telephone central office or in an office building or to various remote terminals are required. However, in order to efficiently couple the signals transmitted by the respective optical fibers, a fiber optic connector must not significantly attenuate or alter the transmitted optical signals. In addition, the fiber optic connector must be relatively rugged and adapted to be connected and disconnected a number of times in order to accommodate changes in the optical fiber transmission path.
A wide variety of factory and field-installed fiber optic connectors are known. It is desired to have an optical fiber connector that is inexpensive to manufacture, easy to install and is capable of withstanding a wide range of environmental factors. In factory-installed connector designs, the connector is coupled with the end of one or more optical fibers during a factory assembly process. Factory installation of the fiber optic connectors onto the end of the optical fibers allows for increased accuracy in the assembly and construction of the connector and avoids the environmental and technical problems associated with field installation.
It is not always possible to factory install fiber optic connectors on the termination ends of optical fibers in every situation. For example, in widely-deployed networks, the optical fiber that terminates at the customer's premises, known as a field fiber, can vary in the desired length. Similarly, optical fiber installed within a structure may require optical fiber runs ranging from just a few feet to several hundred feet. Furthermore, the physical space limitations may not permit storage of excess fiber length that naturally results when installation is limited by a small number of available fiber lengths. With such varying lengths and the desire to minimize any excess slack on the ends of the optical fiber runs, it is simply not practical to install factory connectors on the fiber because of the uncertainty and variability in the length of field fiber.
Consequently, field-installable optical fiber connectors have been developed which can be coupled onto an end portion of an optical fiber in the field once the particular application and length of the optical fiber has been determined. Although alternative types of connectors are available, one of the most common forms of field-installable connectors is the mechanical splice connector. Mechanical splice connectors create a physical mating between the ends of mating optical fibers. Frequently, these mechanical splice connectors use an internal fiber contained within the connector to mate to the inserted field fiber within the connector. The internal fiber, commonly known as a “stub fiber” or “fiber stub”, usually extends from about the end of a ferrule to approximately halfway along the length of the connector. This stub fiber is factorypolished at the ferrule end, enabling the ferrule and stub to be readily mated with another connector after installation of the connector. The other end of the stub fiber may be either cleaved or polished in the factory and provides a mating surface for engaging with an inserted field fiber.
One of the more important aspects of installing a mechanical splice connector is ensuring that the stub fiber and inserted field fiber are accurately aligned to ensure minimum insertion loss across the fiber-fiber interface. A number of mechanisms are known in the prior art to accomplish the task of accurately aligning the optical fibers. Alignment mechanisms in the art can ensure that the core of the fiber stub and the core of the field fiber are accurately aligned and the field fiber is then locked into position. After the optical fibers are aligned and the field fiber is locked into position, the alignment between the fiber stub and the inserted field fiber must be precisely maintained to provide a consistent, reliable connection.